The present invention relates to an electrical connecting device for a machine.
Electrical machines may be cooled by oil which is distributed freely within an internal space of the machine. Such an electrical machine may be situated in a hybrid vehicle in which it serves alternately as a motor and a generator. Electrical machines of this kind need a connecting device which transfers electrical energy between its stator windings situated within the oil-filled space and a source for storage of electrical energy situated outside the oil-filled space. The connecting device has an internal connection for electric cables which are connected to the electrical machine's stator windings and an external connection for electric cables which are connected to the energy storage source. The internal connection is suited to being in contact with oil, whereas the external connection needs to be kept dry and free from oil. Any oil reaching the external connection would make this part of the connecting device difficult to service. Oil also tends to creep in between the conductors and insulation of electric cables. The oil may thus reach the energy storage source and connecting electrical components via the electric cables and cause problems.
EP 1 541 831 refers to an electric motor and a pump situated in a housing which contains hydraulic oil. An electrical connecting device is situated in an aperture of the housing. The connecting device comprises a platelike element fastened in the housing.
The platelike element has three holes for respective contact pins made of electrically conductive material. Each contact pin is fitted on the platelike element by means of a screw-type portion and a nut. The threaded portion and the nut constitute a threaded connection which in a tightened state has also the function of providing a tight connection between the platelike element and the contact pin in the respective hole.
U.S. Pat. No. 7,494,362 refers to a connecting device for transfer of high voltage between an electric cable situated on the outside of a casing of an electric motor unit and an electric cable situated on the inside of the casing. The contact device comprises a connection unit situated in an aperture in the casing. The connection unit comprises a plurality of components, in particular an electrically conductive means, an internal casing and an external casing. The connection unit is provided with an O-ring which serves as a seal in the space between the hole and the connection unit. The connection unit has a threaded portion by means of which it is screwed firmly in a cuplike retainer fastened to the inside of the casing. Such a connecting device is of relatively complicated configuration.